Conventional telecommunications networks include two distinct communication pathways or subnetworks—a voice network and a signaling network. These two networks function in a cooperative manner to facilitate calls between users. As implied by its name, the voice network handles the transmission of voice (or user data) information between users. The signaling network has a number of responsibilities, which include call setup, call tear down, and database access features. In simple terms, the signaling network facilitates the dynamic linking together of discrete voice-type communication circuits such that voice connections are established between end users. Additionally, the signaling network provides a framework through which non-voice-related information may be transported. This data and transport functionality is transparent to the users. This signaling technique is often referred to as out-of-band signaling, where the term “band” implies voice band. The signaling protocol most commonly employed in communication networks around the world is the signaling system 7 (SS7) protocol, which is also referred to as the common channel signaling (CCS) or CCS7 protocol.
From a hardware perspective, an SS7 network includes a plurality of SS7 nodes, generically referred to as signaling points (SPs). SS7 nodes are interconnected using signaling links. At least three major types of SPs may be included in an SS7 network: service switching points (SSPs), signal transfer points (STPS) and service control points (SCPs). Within an SS7 signaling network, each SP is assigned an SS7 network address, which is referred to as a point code (PC).
An SSP is normally installed in Class 4 tandem or Class 5 end offices. The SSP is capable of handling both in-band signaling and SS7 signaling. An SSP can be a customer switch, an end office, an access tandem and/or a tandem. An STP transfers signaling messages from one signaling link to another. STPs are packet switches and are generally installed as mated pairs. Finally, SCPs control access to databases, such as 800 number translation databases, caller identification databases, credit card verification databases, etc.
A simplified example of an SS7 signaling network, generally indicated by reference numeral 100, is presented in FIG. 1. In FIG. 1, SS7 network 100, which includes an STP 102, a first SSP or end office (EO) 104, and a second end office 106. As illustrated in FIG. 1, each SS7 network node is assigned a point code that uniquely identifies each node within the context of the SS7 network. For example, STP 102 is assigned a point code of 1-0-0, end office 104 is assigned a point code of 2-0-0, and end office 106 is assigned a point code of 2-0-1.
Signaling links are transmission facilities used to connect SPs. Conventional signaling links are dedicated bi-directional facilities operating at 56 kbps in the U.S. and Canada and at 64 kbps when clear channel capability is deployed. Normally, links are installed in pairs for redundancy and enhanced network integrity.
In some modern networks, traditional 56 kbps dedicated SS7 signaling links may be replaced by high-speed signaling links, such as Internet protocol (IP) or asynchronous transfer mode (ATM) signaling links. With particular regard to IP signaling links, the need for such links has arisen in response to the increasing convergence of traditional telecommunications networks and traditional data networks. As this converged network environment continues to evolve, so will the tendency of network operators to place SSP end office nodes within the data network or IP component of the converged network environment. PSTN and wireless telephone network operators will likely find the economics of data network operation favorable to the placement of end office nodes within the data component of the converged network environment, as opposed to the traditional PSTN-SS7 network component. Examples of SSP-like nodes that may be placed in the data network include media gateways (MG) and media gateway controller (MGC) or softswitch (SS) nodes.
In a converged SS7-IP network environment, SS7-capable nodes may be located in an IP network and assigned an IP address. However, in addition to an IP address, such IP-based SSP or end office facilities also require an SS7 point code in order to be accessible to and inter-operable with other nodes in the SS7 network.
FIG. 2 illustrates an exemplary converged SS7-IP network environment, generally indicated by reference numeral 110. In FIG. 2, network 110 includes STP 102 and end office nodes 104 and 106 as described above. In addition, network 110 includes a signaling gateway 112 and a media gateway controller 114. As illustrated in FIG. 2, each node, including MGC 114, in the converged signaling network 110 is assigned a unique SS7 point code address. MGC 114 is also assigned an IP address.
A primary reason for the dual addressing of IP-based SS7 nodes involves network management services as provided by the message transfer part (MTP) portion of the SS7 signaling protocol. That is, in order to communicate with other SS7 nodes, an IP-based SS7 node must have its own point code and must also participate in SS7 network management protocols. A detailed description of such converged SS7-IP signaling network management issues is presented in commonly-assigned, co-pending U.S. patent application No. 09/770,316, filed Jan. 26, 2001, and entitled Methods And Systems For Providing Converged Network Management Functionality In A Gateway Routing Node (hereinafter, “SG Network Management Patent Application”), the disclosure of which is incorporated herein by reference in its entirety. Briefly, the SG Network Management Patent Application discloses a signaling gateway that includes SS7 and IP routing capabilities. When a node or signaling link in an SS7 network goes down, the signaling gateway determines nodes in the IP network that are configured to communicate with the out-of-service node. The signaling gateway notifies these nodes in the IP network to prevent these nodes from attempting to communicate with the out-of-service node or signaling link.
The signaling gateway described in the SG Network Management Patent Application also receives audit messages from nodes in the IP network requesting the status of nodes in the SS7 network. If two or more audit messages regarding the same SS7 node are received within a predetermined time period, the signaling gateway discards the redundant audit messages. This prevents flooding of audit messages in the SS7 network by nodes in the data network. Thus, the SG Network Management Patent Application addresses several problems associated with providing network management in a converged SS7-IP signaling environment. However, the SG Network Management Patent Application does not address problems associated with requiring unique point codes to be assigned to IP nodes in the IP network.
SS7 network point codes are a finite resource that is being rapidly consumed by SS7 network operators. As a result, point codes have become a valuable commodity in recent years. Consequently, network operators that choose to deploy IP-based signaling nodes (e.g., MGC/softswitch nodes) are faced with the problem of consuming valuable SS7 point codes. Therefore, what is needed is a system and method of enabling a network operator to deploy data-network-based (e.g., IP, ATM, etc.) signaling nodes in a converged SS7-data network environment while minimizing or eliminating the need to assign unique point codes to such data-network-based signaling nodes.